1. Field of the Invention
The present invention relates to a transport installation for manufactured products, particularly elements of automobile bodies, and particularly for assembly lines automated with robots.
2. Description of the Prior Art
Making general use of robots or programmable machines to automate an automobile manufacturing transport chain requires a structure below the chain which, while being extremely rigid, provides a nearly optimal clearance allowing maximum work arm range for the robot.
In addition, use of programmable machines make it possible, thanks to multi-programming, for the machine to carry out successively, at will and without interruption, the same assembly operation in the assembly or subassembly of different types of bodies by a simple selection of the program controlling the movements of the machine's working arm. Thus, it is desirable to allow selective introduction into the transport chain of at least two distinct types of mounting supports, each adapted to receive elements of different body types.
It is known to use body element transport installations or chains in automobile assembly lines comprising an upper line, which advances the mounting supports for said body elements, and a lower line, which returns the mounting supports when empty, thereby forming a storage line accumulating said mounting supports and extending below the upper line. Until now these installations have not permitted free selection at will of the mounting supports on the lower return line and accumulation storage, as a function of the immediate need or wish to assemble successively different body types.
It is also very advantageous to be able to selectively secure at least three variants or distinct body element types to the same transport chain. Preferably, these would be bodies intended respectively for a part of a vehicle being produced at a constant rate, a vehicle being produced at a decreasing rate and a vehicle being produced at an increasing rate. This would provide for optimum flexibility during transition periods when production of an outgoing model is being reduced and a new model is being simultaneously phased in.